This invention relates to method and apparatus for tail sealing of convolutely wound webs and, more particularly, to elongated logs such as are produced in manufacturing bathroom tissue and kitchen toweling products.
Webs are often "rewound" into retail sized logs. As exemplified by bathroom tissue and kitchen toweling, the webs from the paper machine are normally wound into a jumbo roll of 5 to 10 feet in diameter and 100 to 200 inches in axial length. These jumbo rolls are then transferred to a "rewinder" where they are rewound into the consumer sized diameter product, viz., 5 to 10 inches in diameter but with an axial length of the original jumbo roll. During this rewinding, the web is normally transversely perforated on 4-1/2" centers for bathroom tissues and 11" for kitchen toweling. Subsequently, these logs are transversely sawed into shorter axial lengths, i.e., 4-1/2" for bathroom tissue and 11" for kitchen toweling so that the "squares" of web material can be unwound and detached. The rewinding normally results in a "loose" tail on the outside of the log which could interfere with either or both of the transverse sawing and the ultimate roll packaging. Therefore, for the last 35 years, tail sealing has been performed and illustrative of an early commercial machine is U.S. Pat. No. 3,044,532. This provided the basic technology of unwinding the tail from the completed log, introducing adhesive between the unwound tail and the underlying convolution, and then rewinding the tail on the log.
Two widely employed improvements are seen in U.S. Pat. Nos. 3,393,105 where adhesive was applied to the tail and 4,016,752 where adhesive was applied to the convolution underlying the tail.
A Japanese 1975 Publication 50-35562 discloses and adhesive applicator which is positioned underneath a log to apply adhesive to one or both of the draped, tail and underlying log convolution.
A 1977 British Publication 1 495 445 discloses a tail sealer where the tail is immobilized by vacuum so as to permit an orbiting brush to apply adhesive to the underlying log.
U.S. Pat. No. 4,475,974 discloses a chain conveyor for positioning a log in different stations for unwinding, glue application and rewinding. U.S. Pat. No. 4,963,223 discloses an orbiting tail sealer with stations for unwinding and gluing. U.S. Pat. No. 5,242,525 discloses an in-line conveyor consisting of two parallel belts for handling the logs during tail sealing. U.S. Pat. No. 5,259,910 shows another conveyor-type tail sealer where adhesive is applied from the underside of the log.
According to the invention, a rotating processing wheel or turret is provided which receives a wound log and which clamps the log for unwinding, adhesive application and rewinding during the orbiting of the turret. This provides a method for sealing the tail of a convolutely wound log which includes providing a processing wheel rotatably mounted in a frame and having a plurality of circumferentially spaced three-roll clusters, feeding into a first cluster a wound log while positioning an immediately previously fed log with a draped tail in another cluster adjacent glue apparatus and while ejecting an even earlier fed log now rewound from still another cluster.
The invention also provides a novel infeed mechanism and procedure which is advantageous both with the above described turret sealer and those employing other sealing techniques. The infeed employs roller means in combination with sensor means to provide a predetermined orientation of the tail of a wound log so that there is no need in the sealer itself for complicated mechanisms to insure proper tail orientation incident to gluing.
Other objects and advantages of the invention may be seen in the details of construction and operation set forth in the ensuing specification.